A full-suspension eMTB weighing 16.3 kg. Is that possible? With the new E-Caliber, 9.9 XTR 2021 and its FAZUA motor, Trek say YES! But does it make sense? We have had the exclusive test of the € 12,000 Trek E-Caliber 9.9 XTR 2021 in Italy. We tell you what the ultralight race bike is capable of and whether XC-ebikes even make sense!

XC is part and parcel of mountain biking. The discipline gained its seal of approval in the ’90s when it was accepted as a sport in the ’96 Summer Olympics. For XC (short for cross country), efficiency, acceleration and endurance are the main priorities. Analogue XC bikes are characterised by their efficient ride and competitively low weight. They’re less suited to comfortable off-road riding due to their aggressive riding position, stiff suspension and lightweight builds. If you’re not an XC pro, it’s usually ill-advised to take on overly challenging trails with all those lightweight components, which only provide a limited margin for error and safety. As such, XC bikes continue to carve out their own, separate niche.

Trek think that XC riding is under-represented in the ebike segment and has set about giving it more attention. The American brand already has a thoroughbred analogue racehorse in its stable in the form of the Trek Supercaliber, but in Trek’s eyes, there’s a large gap between lightweight XC bikes and eMTBs with powerful assistance, that is yet to be filled. The idea isn’t a new one. FOCUS previously presented an XC ebike prototype equipped with a FAZUA motor in 2016, though this was a hardtail. The FOCUS Raven² went into production in 2017 but didn’t experience massive popularity. Nonetheless, we were quite enthusiastic about the concept of a, for the time, genuinely lightweight eMTB, though it’s limits quickly became apparent. Can Trek open up the market with the new E-Caliber?

Made for the podium? The new Trek E-Caliber 9.9 XTR in detail

Trek E-Caliber 9.9 XTR | FAZUA Evation/250 Wh | 120/60 mm (f/r)
16.3 kg (size L) | € 11,999 | Manufacturer’s website

Trek’s analogue Supercaliber was the mentor for the development of the E-Caliber. Like its counterpart, the electric version pursues the same goal of combining the efficient propulsion and low weight of a hardtail with the increased reserves provided by a fully. To put the concept into reality Trek have relied on their IsoStrut technology featured on the Supercaliber, which see the frame become part of the kinematics. The thin seat stays provide enough flex in the rear end to make Trek’s well-known Active Braking Pivot (ABP) on the rear axle superfluous, allowing weight to be saved. The 60 mm travel is controlled by the IsoStrut shock, developed in collaboration with FOX, integrated into the underside of the top tube.

The IsoStrut turns the ebike into a mix between a hardtail and fully.

The frame has a sharp silhouette and the difference in proportions between the super thin seat stays and the wide down tube definitely draw attention. The paint job exudes race flair but, for individualists, can also be configured to your tastes in Trek’s ProjectOne configurator. Cable ports on both sides behind the head tube route cables internally. However, from the rider’s perspective, the cabling around the cockpit is hectic, despite the missing dropper post lever, with a tangle of cables remaining for the motor remote and lockout.

For individualists, Trek offer the option to change the finish to suit your own tastes in their ProjectOne configurator.
At the front of the head tube, more cables come together than at your local telephone exchange.
The thin seat stays offer enough flex to generate the 60 mm travel that is controlled by the IsoStrut shock.

Two bikes in one? The FAZUA Evation system in the Trek E-Caliber 9.9 XTR 2021

For the motor, the American brand has gone with the FAZUA Evation drive which offers many advantages compared to the big players in the motor business. In our big motor group test, the FAZUA unit stood out with its low weight and can even, wait for it, be removed from the frame within seconds. The motor and battery form a 3.36 kg, removable unit, with only the lightweight gearbox between the cranks fixed in the frame. The motor-battery unit can be replaced with a hollow 600 g cover which also doubles as a generous storage compartment. That lets the ebike be ridden as a non-motorised one too, with its riding character coming even closer to that of an XC bike. A further unique feature of the FAZUA motor is the practically non-existent pedalling resistance of the gearbox. That’s noticeable, or much more imperceptible, when you ride with the motor turned off or hit speeds above the 25 km/h assistance limit. The transition at that 25 km/h limit is also very natural. On the other hand, the loud clack of the gearbox freewheel as it re-engages is less smooth.

Without the battery and motor but with the cover in place, the E-Caliber is just under 2.7 kg lighter and can be ridden like an analogue bike. You get two bikes for the price of one, very, very expensive bike.
Built-in beatbox: the battery and motor can be removed from the frame but the gearbox stays in place. It doesn’t have any perceptible pedalling resistance but clacks audibly when its freewheel engages.
Without a battery and motor the frame offers masses of storage space.

Alongside the FAZUA motor, the Trek is also equipped with the new FAZUA Remote bX and the updated 250X battery with a 252 Wh capacity. Like before, the battery can only be charged off the bike but no longer has to be removed to be turned on. Now, the system can now be comfortably activated via the remote. The new bX remote has a sleek touch interface that can be easily operated even while wearing gloves. However, we did miss the haptic feedback of physical buttons and often had to look down to check the coloured LEDs to see which assistance mode we were currently in.

FAZUA deliver their system with Breeze, River and Rocket modes preconfigured. In Breeze mode, the motor delivers a constant 100 Watts. For heavy and very aggressive riders this is hardly detectable. In the progressive River mode, the motor output modulates based on how much effort you’re putting in, though is limited to 210 Watts. In Rocket mode, the motor gives everything it has and increases its output to the maximum 55 Nm torque quickly. With its comparatively low torque and lower maximum power, the motor sits behind Bosch, Brose and Shimano but is more than sufficient for this kind of bike in the majority of situations, fitting the character of an XC bike perfectly. Nonetheless, if you don’t get on with the motor’s handling, you won’t necessarily have to switch to the competition. In terms of connectivity and individualisation, some big manufacturers could learn a thing or two here. With FAZUA’s Toolbox Software 2.0 desktop software, individual assistance mode can be comprehensively tuned to fit your requirements. Alongside the maximum output, the relationship between rider input and motor output, as well as the ramp-up of the motor power for the individual modes can be adjusted. While the Trek E-Caliber eschews a display and only communicates the battery charge and assistance mode via coloured LEDs, if you want more detailed information, you can connect your smartphone, Garmin, Wahoo or other computers via Bluetooth to the remote, giving you an expanded interface on your external display.

When light isn’t light enough – The spec of the Trek E-Caliber 9.9 XTR 2021

The spec of the Trek E-Caliber 9.9 XTR subjects itself unquestioningly to the overall concept and contributes to the low weight of the bike. However, to achieve that impressive number, the top-of-the-range model E-Caliber we tested has had to accept some significant compromises in off-road performance with partly questionable component choices. While the three cheapest entry-level models come equipped with a dropper post, the two high-end models come with conventional carbon seatposts. For one thing, that’s a pity because the 270 mm seatpost insertion depth available for size L would be well-suited to a dropper. It’s even more of a shame because Trek claim the E-Caliber is supposed to be ready for more demanding descents than the Supercaliber – but more on this when we talk about the geometry. Weight has been shaved in the wrong place here as lightweight fetishists would no doubt choose the analogue Supercaliber anyway. Even without a motor and battery, the E-Caliber still weighs 13.6 kg. The same applies to the FOX Factory 34 Step-Cast fork with its 120 mm travel. It works perfectly for lightweight riders or on flowing trails but starts struggling to hold its line underneath heavy riders or through rougher terrain. Four-piston Shimano XTR brakes with ICE TECH pads and rotors also find their place on the build. Up front, the rotor is 200 mm large, at the rear just 180 mm and we would have felt more secure on long descents with a larger disc. For the rest of the build, lots of components come from Trek’s in-house brand Bontrager which score across the board with their high quality. Solely the lightweight Bontrager Kovee XXX carbon wheels in combination with the fragile Bontrager XR3 Team Issue tires on our test bikes left us with mixed feelings. They contribute significantly to the light-footed acceleration of the E-Caliber XTR 9.9 but don’t fill us with confidence that they’ll survive rough sections unscathed in the long run, particularly if you want to ride sensibly low tire pressures.

The top-end models eschew a dropper post in favour of maximum weight savings. What contributes to an impressive weight on paper leads to significant restriction of freedom of movement on the trail.
The lightweight Bontrager XR3 Team Issue tires on the Kovee XXX carbon rims ensure low rolling resistance and good acceleration. Grip and protection are limited though.
Up front, the FOX 34 Step-Cast fork delivers 120 mm travel. Unfortunately, for demanding trail use and heavy riders it’s under dimensioned.
The four-piston Shimano XTR brakes are a good choice…
… but the 180 mm rotor at the rear is overwhelmed when faced with heavy riders and long descents.

Trek E-Caliber 9.9 XTR

€ 11,999

Specifications

Motor FAZUA Evation 55 Nm
Battery FAZUA Evation 252X 250 Wh
Display -
Fork FOX 34 Factory Step-Cast FIT4 mit Remote 120 mm
Rear Shock Trek IsoStrut, FOX Performance shock 60 mm
Seatpost Bontrager XXX
Brakes Shimano XTR M9120 200/180 mm
Drivetrain Shimano XTR 1x12
Stem Bontrager Kovee Pro 70 mm
Handlebar Bontrager Line Pro 750 mm
Wheelset Bontrager Kovee XXX 29"
Tires Bontrager XR3 Team Issue 2.4"

Technical Data

Size S M L XL
Weight 16.3 kg

Other builds

As is typical for Trek, high-end builds are offered with both Shimano and SRAM components. The entry-level model starts at € 6,799 while you’ll leave your Trek dealer with the luxury build, equipped with wireless SRAM Eagle AXS shifting, for € 12,999.


Trek E-Caliber 9.6

€ 6,799

Specifications

Motor FAZUA Evation 55 Nm
Battery FAZUA Evation 252X 250 Wh
Display -
Fork RockShox 35 Gold RL 120 mm
Rear Shock Trek IsoStrut, FOX Factory shock 60 mm
Seatpost TranzX JD 100–130 mm
Brakes Shimano MT4100
Drivetrain Shimano DEORE/XT 1x12
Stem Bontrager Rhythm Comp 60–70 mm
Handlebar Bontrager Comp 720–750 mm
Wheelset Bontrager Kovee Comp 29"
Tires Bontrager XR3 Team Issue2.4"

Technical Data

Size S M L XL
Weight 18.49 kg (Info by Trek in size M)


Trek E-Caliber 9.8 GX

€ 8,399

Specifications

Motor FAZUA Evation 55 Nm
Battery FAZUA Evation 252X 250 Wh
Display -
Fork RockShox SID Select+ 120 mm
Rear Shock Trek IsoStrut, FOX Factory shock 60 mm
Seatpost Bontrager Line Elite Dropper 100–150 mm
Brakes SRAM G2 RSC
Drivetrain SRAM GX-Eagle 1x12
Stem Bontrager Kovee Pro 60–70 mm
Handlebar Bontrager Line Pro 750 mm
Wheelset Bontrager Kovee Pro 29"
Tires Bontrager XR3 Team Issue 2.4"

Technical Data

Size S M L XL
Weight 16.99 kg (Info by Trek in size M)


Trek E-Caliber 9.8 XT

€ 8,399

Specifications

Motor FAZUA Evation 55 Nm
Battery FAZUA Evation 252X 250 Wh
Display -
Fork RockShox SID Select+ 120 mm
Rear Shock Trek IsoStrut, FOX Factory shock 60 mm
Seatpost Bontrager Line Elite Dropper 100–150 mm
Brakes Shimano XT
Drivetrain Shimano XT 1x12
Stem Bontrager Kovee Pro 60–70 mm
Handlebar Bontrager Line Pro 750 mm
Wheelset Bontrager Kovee Pro 29"
Tires Bontrager XR3 Team Issue 2.4"

Technical Data

Size S M L XL
Weight 16.94 kg (Info by Trek in size M)


Trek E-Caliber 9.9 XX1 AXS

€ 12,999

Specifications

Motor FAZUA Evation 55 Nm
Battery FAZUA Evation 252X 250 Wh
Display -
Fork RockShox SID Ultimate 120 mm
Rear Shock Trek IsoStrut, FOX Factory shock 60 mm
Seatpost Bontrager XXX
Brakes Shimano XTR M9120
Drivetrain SRAM XX1 Eagle AXS 1x12
Stem Bontrager Kovee Pro 60–70 mm
Handlebar Bontrager Line Pro 750 mm
Wheelset Bontrager Kovee XXX 29"
Tires Bontrager XR3 Team Issue 2.4"

Technical Data

Size S M L XL
Weight 15.77 kg (Info by Trek in size M)

Supercaliber PLUS – The geometry of the E-Caliber 9.9 XTR in detail

The Trek E-Caliber’s measurements are guided by the proven Supercaliber platform. Nonetheless, the engineers have made a few modifications to allow fast XC riders to feel more comfortable at high speeds. At 67.5°, the head tube angle of the E-Caliber is 1.5° slacker than the Supercaliber. The reach across all sizes is between 0.5 and 1.5 cm longer than the Supercaliber and the stack increases by between 1.5 and 2.8 cm compared to the analogue counterpart. The E-Caliber is available in four sizes between S and XL. A Mino Link, as found on many Trek bikes to adjust geometry, isn’t present here.

Size S M L XL
Seat tube 394 mm 419 mm 470 mm 508 mm
Top tube< 580 mm 617 mm 648 mm 670 mm
Head tube 90 mm 100 mm 105 mm 110 mm
Head angle 67.5° 67.5° 67.5° 67.5°
Seat angle 72.3° 72.6° 72.8° 72.8°
Chainstay 447 mm 447 mm 447 mm 447 mm
BB Drop 50 mm 50 mm 50 mm 50 mm
Wheelbase 1,126 mm 1,165 mm 1,197 mm 1,219 mm
Reach 405 mm 440 mm 470 mm 490 mm
Stack 609 mm 618 mm 622 mm 627 mm

Fast uphill, exactly 25 km/h on the flats and slow downhill – First ride review of the Trek E-Caliber 9.9 XTR 2021

We shot along the best XC tracks in Tuscany aboard the Trek E-Caliber, where many pros and several World Champions regularly train. We went on tours and, of course, tested the bike on our favourite local trails around Stuttgart to gather our first impressions of this new breed of ebike. Getting on it, it’s immediately clear that the riding position of the E-Caliber differs from the usual aggressive racing position of the analogue XC bikes we know. The wide bars and higher front puts less stress on the arms and back, theoretically making the E-Caliber suited to tours as well. However, in practice, the build and the very specific concept limits the bike’s suitability here – more on this later. With the first push on the pedals and with maximum motor support, you feel like an XC pro, fuelled with carbs after a pasta fest. The E-Caliber surges forward lightly and in the lower assistance modes, the motor contributes to the job at hand, staying unobtrusively in the background. In the dynamic and easily modulated River mode, it’s easy to accelerate out of corners. Here the E-Caliber can show off its racing flair and is a lot of fun. The 25 km/h assistance limit is reached after just a few pedal strokes and the motor fades its assistance away very naturally.

The riding position of the E-Caliber is more relaxed than the first glance might suggest.
No, we aren’t lost. Some nice places in Tuscany are only to be found if you know the hidden paths well.

If you’re riding with a quicker group of riders and are on the E-Caliber then, if you’re in Europe, you’ve drawn the short straw – above 25 km/h the weight penalty over analogue XC bikes has to be compensated for by your own power. In places like the USA, where the motor is allowed to assist up to 32 km/h, you’ll be much better placed to keep up with the pack.

The stiff suspension of the E-Caliber is fairly neutral. Even with uneven pedalling that would usually elicit bobbing from the suspension, the consistent support of the FAZUA motor ensures that this is compensated with constant tension on the chain, reducing suspension bob. Here the E-Caliber even outshines its analogue sibling, the Supercaliber. However, the grip to activate the lockout could have been spared and the efficient rear end and 60 mm travel IsoStrut damper are only there to take the spikes out of impact, even when fully open. They generate neither much comfort nor do they help the rear wheel gain significant amounts of traction on uneven terrain. That becomes clear as soon as you take the E-Caliber up a climb, where it feels more like a hardtail.

Uphill with the Trek E-Caliber 9.9 XTR 2021

Flowing trails uphill are the E-Caliber’s speciality, where it’s exceptionally fast. As long as there’s enough grip, the FAZUA system can make full use of its power and the light-footed E-Caliber responds to every steering input along winding trails. As the climbs get steeper, the E-Caliber leaves its comfort zone. The front wheel lifts quite early and the front has to be weighted actively so that you stay in contact with the ground, don’t lose traction and continue to hold the line you envisaged. As the FAZUA motor doesn’t deliver the same power as motors in the Bosch league, the rider has to be more active and get out of the saddle on numerous occasions. Nonetheless, over steps, you have to be careful to modulate your power sensitively to avoid the rear wheel spinning out. The lightweight and low-profile Bontrager XR3 Team Issue tires just aren’t designed for maximum grip, instead focussing on efficiency and low rolling resistance. You also can’t rely on extra traction from the suspension, which is generally too stiff to keep the rear wheel stuck to the ground.

Uphill flowing sections is where the Trek E-Caliber 9.9 XTR 2021 is completely in its element.
Helmet Giro Synthe MIPS | Glasses Uvex Sportstyle 228 | Jacket Specialized Deflect Swat | Jersey 100% R Core | Shorts 100% Celium | Shoes Five Ten Kestrel Lace | Socks Stance

The Trek E-Caliber downhill

Having arrived at the top of the trail, rather than settling into the bars, you’ll first reach for the multi-tool in your jersey. Our top-end model doesn’t have a dropper post, meaning the carbon seatpost has to be lowered manually. Only practised XC racers can deal with a high saddle and the lacking freedom of movement that entails. On flowing and not all too technical or steep descents, the Trek E-Caliber rides similarly to a manoeuvrable hardtail and does well at moderate speeds. The stiff rear provides lots of support to generate speed through rollers and other features when riding actively. The additional mass of the motor and battery have little impact and the E-Caliber can be easily manoeuvred by beginners with no surprises in the handling.

As the trails get more demanding, the weight-conscious components quickly put a damper on the fun. Without a dropped saddle, the freedom of movement aboard the Trek E-Caliber is severely restricted. The lightweight FOX 34 Step-Cast fork tends to flex when ridden by heavier riders or ridden aggressively, resulting in imprecise handling when changing direction quickly, braking hard or on technical terrain. The lightweight tires again entail a compromise, this time between having enough air pressure to prevent punctures and finding traction on the trail. The small disc rotor on the rear is pushed to its limit on sustained descents by heavy riders. In contrast to conventional fullys, the stiff rear end doesn’t give up its travel willingly and only starts moving under big impacts, like steps, only preventing you from being bucked off the pedals.

On steep terrain, the missing dropper post limits freedom of movement significantly. The lightweight components also convey a limited sense of security.
For jumps, you can rely on the support of the rear end. However, it doesn’t deliver a comfortable ride. The IsoStrut shock only absorbs the peak forces from big impacts while riding. Don’t expect sensitive or plush comfort.

Tuning tip: fit a dropper post!

Who and who isn’t the new Trek E-Caliber XTR 9.9 for?

The development of an E-XC bike is a bold and, without a doubt, costly step for Trek. The brand wouldn’t have gone down this path if they couldn’t count on a suitable customer base. As such, who is the Trek E-Caliber for? In all honesty, answering this question is quite hard. One thing is clear: it’s a fairly niche target audience. Here are our insights:

The XC-ebike concept is a bold step for Trek.
  1. The Trek E-Caliber we tested is suited to XC-pros who want to achieve a training load during easy training or rest phases that wouldn’t be possible in the same way on an analogue XC bike. For example, an E-XC bike would make training at a constant effort possible, with the motor assistance modulating its support based on the heart rate. Unfortunately, the E-Caliber and FAZUA system are missing this functionality, which does already exist for the Specialized Levo SL. Truth be told, the size of this audience is likely thinner than the Lycra worn at sunny XC races.
  2. The second target group could be ambitious XC riders who can’t yet match the speed of experienced and stronger riders without support. Here, Trek could position the E-Caliber as the big equaliser that allows riders of different abilities to ride together, with the motor compensating for differences in power output. However, here the XC-ebike will face the same fate as E-road bikes, which have to struggle with the 25 km/h assistance limit in Europe and have only disadvantages compared to analogue bikes at higher speeds.
  3. Riders on the search for a lightweight ebike with a marathon feeling for long riders could find their money’s worth with the Trek E-Caliber. That means the Trek could also present a viable alternative to the E-gravel bike. While with its limited and natural support the Caliber has qualities well-suited to discovering new terrain, the aggressive geometry and position engender disadvantages for long-distance comfort. On top of that, the weight-conscious components mean that any riders that aren’t featherweights will face challenges on difficult terrain. Besides, the competition in the Light eMTB category is already at an extremely high level, for example in the form of the Specialized Levo SL and the Orbea Rise. Even if they’re not the most obvious competition from the specs, the weight increase for these is less than a kilogram, though their range of applications is significantly expanded!
    If you’re looking for an ebike with a marathon feeling for quick post-work rides on gravel track and easy trails, you might have found a suitable platform, as long as the price doesn’t represent a barrier. We just can’t predict whether the E-Caliber will be a bestseller or will languish on the shop floor

Looking for something hot, new and sexy? The Trek E-Caliber is somehow special and not every ebike concept has to be based on rational choices. It’s ok for it to be just sexy or inspiring. What do you think? Maybe you have an idea of what you need an E-XC-bike for. If you do, we’d be happy to hear your feedback about the new Trek E-Caliber.

Our impressions of the Trek E-Caliber 9.9 XTR 2021

With the E-Caliber 9.9 XTR, Trek have entered the uncertain market of XC-ebikes, whose potential has not yet been proven. The top-end model we tested here is uncompromisingly specced for weight savings but this significantly limits where it can be used. On easy, flowing trails or the quick post-work lap on gravel it will wow marathon enthusiasts into a smile with its motor support. On demanding terrain or for heavier riders, the bike quickly reaches its limits. Apart from its niche application, we think the spirit and purpose of an XC-ebike are very limited. Other Light eMTBs might seem completely different based on their specs but offer a much wider range of uses for the money, especially for those who are looking for a lightweight and touring-capable eMTB.

Tops

  • light-footed handling
  • appealing and customisable motor concept
  • look with guaranteed race flair

Flops

  • limited range of application
  • weak trail performance
  • missing dropper post
  • high price

For more information visit trekbikes.com


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Words: Rudolf Fischer Photos: Valentin Rühl

About the author

Rudolf Fischer

In his previous life Rudolf was a dab hand at promoting innovation, putting his brain behind big-ticket patent assessments that easily ran into six-or-seven-plus figures. These days, the self-confessed data nerd’s role as editor at DOWNTOWN and E-MOUNTAINBIKE is no less exciting. Given his specialism in connectivity, Rudolf’s often placed on the front line of future mobility conversations, but he’s also big into testing new bikes–both on the daily as a committed commuter and intensively for our group tests. The business economist graduate is as versatile as a Swiss penknife, and that’s no hyperbole. Away from two wheels, his background in parkour means he’s a master of front, side and backflips, plus he speaks German, English, French, Russian and a touch of Esperanto. Japanese remains woefully unmastered, despite his best home-learning attempts. Good to know: Rudolf’s sharp tongue has made him a figure of fear in the office, where he’s got a reputation for flexing a dry wittiness à la Ricky Gervais... interestingly, he's usually the one laughing hardest.